1. Field of the Invention
The present invention relates to the manufacture of turbine engine components and, in particular, the finishing of components produced by smelting or forging.
More generally, the invention relates to the finishing of blank components, of final dimensions, which still require final machining, or finishing. In particular it applies to smelted or forged turbojet engine blades.
2. Description of the Related Art
Turbine blades of turbine engines are generally made using the so-called “lost wax” technique, which directly produces the required shape for most of the component, without the need to produce a blank which then has to be machined to create the final shape. However, this technique still necessitates final machining, which comprises operations on the leading edge to remove transferred grains, operations on the trailing edge to remove a trailing edge strip and operations on the platform for its connection to the surface of the vane.
The smelting technique is not completely effective for producing very thin faces (or partitions), such as, for example at the trailing edges of blades and their ventilation air evacuation vents. In order to overcome this problem, the thin ends of the blades are smelted with a thickened portion, which is then removed by machining at the end of the manufacturing process. The problem with this method is that it is necessary to calibrate the reference for positioning the blade in the space used for this machining with that of the vane as it comes from the foundry. In the prior art the reference used is taken on the root of the blade and the vane is machined from the reference points taken on this root. This method gives rise to numerous dimensional irregularities and is time-consuming to implement. Because of the possible discrepancy between the reference taken on the root and that of the vane, there is often a lack of precision at the connection between the surface of the vane and the machined surface, with the appearance of projections on the surface of the component.
Moreover, a digitally controlled machine tool would ideally be used for these finishing operations to avoid dimensional irregularities.